This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. In order to get insights into the function of this new family of virulence factors it is crucial to ascertain the conformation of the TIR domain inside the signaling active full length homodimer. We expect SAXS data to give us the orientation of the dimer: is the TIR domain opposing the TIR of the partner molecule or the N-terminal helical region? Having solved the structure of the TIR domain, our top priority is to find a quick method that could provide empirical evidence of the dimer organization because of its functional relevance.